I have had the same problem happen, but here's likely what it is:
Either the resistor has blown, the wiriing harness has fried, or both, - or - it is the blower motor that needs to be replaced.
In any case, here's how to do it:
Check the resistor, its the easiest thing to do first. On the passenger side, under the dash -- WAY UNDER, by almost to the back, there is a wire that goes into the resistor.
The resistor controls the speed of the fan that blows.
There are 2 small screws holding the resistor in, unscrew them and remove the resistor - it is about 3 inches long and 2 inches wide and has ceramic covering. Remove the wiring harness and check both - if resistor is black anywhere, its probably bad. If the wiring harness is melted, and it probably will be, then it needs to be replaced.
Search online for a "Blower Motor Wiring Harness", you'll have instructions on how to cut the wires, splice the new harness and reconnect it. Also you'll need to replace the resistor.
One from the dealer will run you about $150.00, but I got one on parts.com for $26.00 + $10.00 shipping.
If you find that the wiring is fine, then its probably the blower motor.
Underneath the passengers side dash is a panel that covers the blower motor. Remove it, and youll see the blower motor. It looks like a hamstercage, circular with groves throughout its perimiter.
There are four screws holding it in, unscrew them, remove the wiring harness and take out the motor. Theres ways to test to see if it is the motor thats bad, but it requires a multimeter and some familiarity of where you're poking around. A new one will cost you some cash, but I picked up a used on on eBay for about $20.
Replace that, and it should come back on.
The problem though, is most likely the wiring, since GM has already put out a TSB with this wiring problem, and has since replaced the harness with a new model.
questions? email at
[email protected]